Going the distance

— -- In the third set of his fourth-round match, when it became clear that victory would not be his, Fabio Fognini kicked into clown mode.

Surreptitiously, he tried to knock the Panama hat off a security guard on his way to a changeover. Then the free-spirited Italian poured water on himself and made antic gestures to the crowd.

His good friend, Novak Djokovic, couldn't help but smile. They grew up training in Italy and he has seen this lounge act many times.

"I know him for long time, so for me it's funny," Djokovic said after dropping only five games, "but I did not try to laugh too much about it. I tried to direct my focus on my side of the court, what I need to do, not pay attention on him, even though he was funny at times, I have to say."

The quarterfinals, rest assured, will be a joke-free zone. That's because on Tuesday the No. 2-seeded Djokovic meets No. 8 Stanislas Wawrinka. Lately, their Grand Slam matches have been as serious as a New Jersey traffic jam -- and, unlikely as it seems, even longer.

A year ago, Djokovic prevailed over Wawrinka in a fourth-round match that ended 12-10 in the fifth set and went a dizzying 5 hours, 2 minutes. Their semifinal match at the US Open in September was another max-distance five-setter but consumed a more modest 4 hours, 9 minutes.

"I have to be ready to play another 12-10 in the fifth like last year," Djokovic told reporters. "I know that he's playing the tennis of his life in last 15 months. He is confident. You could feel that mentally when he comes to the court, he believes in himself more.

"You cannot expect a clear favorite in that match."

That was exceedingly generous. Although the 28-year-old from Switzerland is playing the best tennis of his life -- he's ranked a career-high No. 8 among ATP World Tour players and has won all eight of his matches in 2014 -- this is Djokovic we're talking about.

A variety of numbers suggest Djokovic will work his way into the semifinals, opposite the winner of No. 3 David Ferrer versus No. 7 Tomas Berdych. Despite their ultra-competitive matches last year, Djokovic owns a 15-2 head-to-head advantage over Wawrinka. And then there is the small matter of his success in this tournament: Djokovic is attempting to win his fourth consecutive men's title here, something never accomplished in the Open era. Aussie Roy Emerson, the pride of Queensland, won five straight from 1963 to '67.

There was a time not so long ago when Djokovic was always a threat to retire from a major match when he arrived at a difficult moment. Now, he has reached 19 consecutive Grand Slam quarterfinals. If that sounds like a lot, you're right. Only Roger Federer (36) and Jimmy Connors (27) produced longer streaks.

Speaking of streaks, Djokovic has won 28 straight matches, going back to last year's US Open final, when he lost to Rafael Nadal. That, it seems, is not a coincidence. Since then, he has run the table in Beijing, Shanghai, Paris and the ATP World Tour finals in London. The two have pushed each other onward and upward for four years now, earning the year-end No. 1 ranking twice each.

No one is playing better than Djokovic and Nadal, and there is a strong likelihood they'll meet again in the final.

Wawrinka isn't far behind. Continuing his late-season momentum from 2013, he won his first tournament of the year, in Chennai. Wawrinka came into his fourth-round match with Tommy Robredo with a losing 6-1 head-to-head record, but dispatched the 31-year-old in straight sets.

Afterward, reporters asked him if he expected another marathon with Djokovic.

"I don't know what to expect," Wawrinka said. "He's an amazing player, especially in the Grand Slams. I watched him a little bit today. He's really, really tough to beat. I didn't find the solution to beat him.

"I need to play my best tennis to have a chance to beat him."

To have a chance …

That's probably as accurate an assessment as you will find.

The funny thing? They could meet again in two weeks when Serbia hosts Switzerland in the first round of Davis Cup. Wawrinka will play, but Djokovic -- who led his country to the final a year ago before falling to the Czech Republic -- has yet to commit.

"I'm focused on the next match, not Davis Cup," Wawrinka said.

Too early to discuss Davis Cup, Djokovic was asked after beating Fognini?

"Too early," he said, smiling. "Let's focus on this one first."